Our research efforts have focused on developing selective muscarinic agonists for the treatment of Alzheimer's disease. We have identified several active ligands with promising biological activity that serve as lead compounds for the development of novel, selective, and centrally-active muscarinic agonists. This project focuses on the design, synthesis, and biological testing of novel amidine-containing compounds as selective muscarinic agonists. Chemical synthesis focuses on a few key compounds with the aim of improving potency, selectivity and central activity in a series of 1, 4, 5, 6-tetrahydropyrimidine derivatives. The overall goal of the proposed studies is to identify a compound with biological activity warranting further development as a drug candidate for the treatment of Alzheimer's disease. EI-MS and FAB-MS have been used for identifying compounds, especially from novel synthetic routes. Mass spectral data have helped verify the existence of new compounds, and help direct further synthetic studies.